A rescue effort on snow-covered Mount Baldy airlifted all four who had been aboard to safety after their helicopter crippled in a hard landing. Two were hospitalized.

"I'm just glad everyone walked out and no one's gushing blood right now," said passenger William Francis. "Just out of nowhere, we lost altitude."

The Robinson R-44 helicopter went down Thursday morning shortly before noon. A responding Sheriff's rescue helicopter carried the pilot and three passengers to a lower elevation. From there, one of the injured was flown to a trauma center. A second was transported by ground ambulance. Their injuries did not appear life-threatening, according to the San Bernardino County Fire Department.

The helicopter, based in Fullerton, had been chartered by a group with cameras and plans to record video. One brought a drone.

What led to the hard landing is under investigation. There were indications it was a planned landing that went awry. It appeared to one passenger that the pilot did not recognize a problem until moments before touchdown.

"We were just going fast and I heard him say 'oh, (expletive),'" said one passenger, who asked not to be identified.

Extensive damage was visible to the helicopter's tail section and rotor, and a cockpit window popped out.

"From what I understand it was a pretty hard landing," said Doug Nelson, a Battalion Chief with the San Bernardino County Fire Department. "They're very lucky it was on top of the ridge and not to the side of the ridge."

The helicopter went down just west of the summit of Mount San Antonio, commonly known as Mount Baldy, elevation 10,064 feet, the highest point in Los Angeles County. The peak is in the San Gabriel Mountains National Monument and Angeles National Forest. The summit is reachable by a hiking trail from the east side, and the initial emergency call came from a hiker who saw the helicopter go down, Nelson said.

That call went to San Bernardino county, and one of its Sheriff rescue airships was first to respond, as did a helicopter from the Los Angeles County Sheriff's department. Within hours of the rescue, a representative of the Federal Aviation Administration was airlifted to the scene to investigate before the expected arrival Friday of a weather front. The National Transportation Safety Board was also notified.

The helicopter has previously been used for aerial tours offered by Hangar 21 at Fullerton Airport. The incident did not occur during a company tour, according to Rob Sims, who said the helicopter had been rented by the pilot for a charter flight.

Plans to remove the damaged helicopter from the ridge have yet to be made.